Field
The present invention relates to a fuel cell system.
Related Art
Conventionally, in fuel cell systems having a tank that stores fuel gas for supplying a fuel cell, the pressure value in the tank is detected. For instance, in the fuel cell system described in JP2002-089793A, a pressure sensor is disposed in piping that supplies hydrogen gas from a tank to a fuel cell, and the pressure value in the tank is detected using such a pressure sensor. Additionally, in this fuel cell system, the amount of hydrogen remaining in the tank is calculated based on the detected pressure value in the tank and the temperature in the tank. Generally, the amount of hydrogen remaining in the tank is expressed using the filling factor of the hydrogen gas in the tank, the so-called state of charge (SOC).
In the fuel cell system described in JP2002-089793A, the pressure value in the tank is incorrectly detected by the pressure sensor when so-called drift, in which the zero point fluctuates, occurs. In particular, when the zero point fluctuates in the positive direction and the pressure value detected is higher than the actual value, the filling factor of hydrogen gas in the tank is calculated to be higher than the actual value, creating a risk of hydrogen gas deficiency suddenly occurring while the fuel cell is functioning. Additionally, in moving bodies such as fuel cell vehicles that are equipped with fuel cell systems, for configurations in which distance to empty is estimated based on the hydrogen gas filling factor, the distance to empty is overestimated if the filling factor is calculated to be higher than the actual value. Hence, there is a need for technology that prevents the pressure value in the tank from being incorrectly detected to be higher than the actual value. Problems such as these are not limited to fuel cell systems equipped in moving bodies, but are common in a variety of fuel cell systems used as a fixed source of power and the like.